I always liked Leadco - decent leads, volume and a liberal return policy. There seems to have been some confusion over their exclusive leads.
They set a firm price and agents were getting decent lead flow. All of a sudden quantity went down and I heard it turned into a bidding system - however never confirmed.
It's true, I've been buying their leads for a while and was told by a guy named Kevin there that if I pay more for leads than their standard price, than I would receive more leads.